Arc ion plating device and method for complex-structure inner cavity of large-length-diameter-ratio pipe fitting

Abstract

The invention discloses an arc ion plating device and method for an inner cavity of a complex structure of a large-length-diameter-ratio pipe fitting, and the device comprises a sealing system, a vacuumizing system, an arc ion plating target material system, a cooling system, an air supply system, a temperature measurement system and a motor balance damping system, wherein the sealing system comprises sealing plates for sealing the two ends of the to-be-machined large-length-diameter-ratio pipe fitting, and the sealed large-length-diameter-ratio pipe fitting serves as a vacuum chamber and is installed on the fixing frame through a bearing device; the vacuumizing system comprises a mechanical pump, a molecular pump and two groups of vacuum gauge tubes; the arc ion plating target material system comprises a cylindrical arc target material and a permanent magnetic field arranged in the arc target material; the motor balance damping system comprises a balancer and a damper; the cooling system is used for cooling the sealing system, the arc ion plating target material system and the motor balance damping system; the gas supply system comprises a gas cylinder, a gas flowmeter and a gas supply pipe; the temperature measuring system comprises a thermocouple and a temperature controller.

Description

Technical Field

[0001] The invention relates to the field of arc ion plating coating preparation, and in particular to an arc ion plating device and method for the inner cavity of a pipe with a large aspect ratio and a complex structure, which is used for preparing a comprehensive coating that is corrosion-resistant, wear-resistant, and ablation-resistant. Background Art

[0002] In actual industrial applications, there are a large number of pipes with large aspect ratios in the oil, natural gas, chemical industry, and aircraft landing gear. Especially in the military field, such as torpedo and missile launch tubes, there are also complex internal structures. In addition, they are subjected to the combined effects of high temperature (up to 3000K), high pressure (up to 500MPa), and complex chemical gas environment (CO, CO2, H2, N2, H2O, etc.) during service. The resulting expansion of the inner diameter of the pipe and the change of the surface geometric structure will seriously affect the shooting accuracy and cause the pipe to fail. In addition, for the inner wall of the aircraft landing gear, the same complex service environment causes the change of the inner surface state of the pipe, which often causes the contact pair to stick to it, resulting in a rigid connection between the fuselage and the landing gear, causing irreversible serious accidents during the landing of the aircraft. Therefore, it is of great significance for the development of aviation and military technology that such large aspect ratio complex internal cavity pipes can maintain the comprehensive performance of corrosion resistance, wear resistance and ablation erosion resistance for a long time and reliably.

[0003] Surface modification technology can significantly improve the overall performance of the substrate without changing its original mechanical properties. At present, electroplated Cr coating is often used to improve the performance of such large aspect ratio and complex inner cavity pipes. However, sulfuric acid and hexavalent Cr in the electroplating solution pose serious environmental hazards. Under the current trend of environmental protection and sustainable development, reasonable and effective surface protection technology is urgently needed to replace the electroplated Cr layer to improve the service life and reliability of pipes. As far as the coatings currently developed are concerned, Cr coatings have good high-temperature stability, excellent corrosion resistance, and good wear resistance. They show more outstanding advantages than Ta, W, Co and other coatings in improving the wear resistance, corrosion resistance and high temperature resistance of pipes. Therefore, green Cr coating technology is still the most promising and effective in improving the overall performance of pipes. The key lies in improving the comprehensive strength and toughness of the Cr layer and its durability.

[0004] Arc ion plating technology is environmentally friendly and green, does not have the problem of hydrogen permeation into the substrate, has good plating performance, fast plating speed, and high bonding strength between the coating and the substrate. It has outstanding advantages in preparing coatings on the surfaces of complex components. However, existing arc ion plating equipment cannot meet the requirements of coating preparation on the complex inner cavity surfaces of pipes with large aspect ratios, and corresponding preparation devices and methods need to be developed. Summary of the invention

[0005] The object of the present invention is to provide an arc ion plating device and method for the inner cavity of a complex structure of a large aspect ratio pipe, which is used to prepare coatings for the inner cavities of different types of large aspect ratio pipes.

[0006] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0007] An arc ion plating device for an inner cavity of a pipe with a large aspect ratio and a complex structure, comprising a sealing system, a vacuum system, an arc ion plating target system, a cooling system, an air supply system, a temperature measurement system and a motor balancing and damping system, wherein:

[0008] The sealing system includes sealing plates for sealing both ends of the large aspect ratio pipe to be processed, and the sealed large aspect ratio pipe serves as a vacuum chamber and is mounted on a fixed frame through a bearing device;

[0009] The vacuum pumping system includes a mechanical pump, a molecular pump and two sets of vacuum gauges; the mechanical pump and the molecular pump are connected to the front end of the vacuum chamber to evacuate the vacuum chamber; the two sets of vacuum gauges are respectively installed at the front end and the rear end of the vacuum chamber along the length direction of the vacuum chamber to measure the vacuum degree of the vacuum chamber;

[0010] The arc ion plating target system comprises a cylindrical arc target and a permanent magnetic field built into the arc target, wherein the arc target is arranged inside a vacuum chamber and installed at the front end of a connecting rod; the connecting rod passes through the rear end of the vacuum chamber, the rear end of the connecting rod is located outside the vacuum chamber and installed on the output shaft of a rotating motor, so as to realize that the arc target rotates around the axis of a large aspect ratio pipe and moves at a uniform speed along the axis of the large aspect ratio pipe at the same time; the magnetic field direction of the permanent magnetic field is perpendicular to the axis of the arc target;

[0011] The motor balancing and shock absorbing system comprises a balancer and a shock absorber, the rotating motor is mounted on the balancer and the shock absorber, the bottom of the rotating motor, the balancer and the shock absorber are mounted on a slide rail through a bracket with rollers, and the slide rail is arranged parallel to the axial direction of the vacuum chamber;

[0012] The cooling system is used to cool the sealing system, arc ion plating target system and motor balance and vibration reduction system;

[0013] The gas supply system includes a gas cylinder, a gas flow meter and a gas supply pipe; the gas cylinder is connected to the rear end of the vacuum chamber through the gas supply pipe, the gas flow meter is installed on the gas supply pipe, and a gas cylinder valve is installed on the gas cylinder;

[0014] The temperature measurement system includes a thermocouple and a temperature controller, which are used to measure the real-time temperature of the vacuum chamber.

[0015] Furthermore, a vacuum connection hole is reserved in the middle of the sealing plate at the front end of the large aspect ratio pipe, and a thermocouple mounting hole and a pair of vacuum gauge mounting holes are reserved at the lower part; an ion plating connection hole is reserved in the middle of the sealing plate at the rear end, and an air supply hole and a pair of vacuum gauge mounting holes are reserved at the lower part.

[0016] Furthermore, the bearing device adopts an arc-shaped fixing card and is supported on the bottom of the side wall of the vacuum chamber so that the axial direction of the vacuum chamber is parallel to the horizontal plane.

[0017] Furthermore, an exhaust pipe is connected to the vacuum connection hole, the exhaust port of the mechanical pump is connected to the exhaust pipe through a pipeline equipped with a pre-exhaust valve, and the air outlet of the mechanical pump is connected to the atmosphere; the exhaust port of the molecular pump is connected to the exhaust pipe through a pipeline equipped with a high valve, and the air outlet of the molecular pump is connected to the exhaust port of the mechanical pump through a pipeline equipped with a pre-stage valve.

[0018] Furthermore, the mechanical pump is used to pump the pressure of the vacuum chamber from atmospheric pressure to 4-5 Pa, while the molecular pump is used to pump the pressure of the vacuum chamber from 4-5 Pa to 1×10 -3 Pa.

[0019] Furthermore, the connecting rod passes through the ion-plated connecting hole on the sealing plate at the rear end of the vacuum chamber, and the connecting rod and the ion-plated connecting hole are threadedly sealed.

[0020] Furthermore, the axis of the arc target coincides with the axis of the vacuum chamber, and the difference between the inner diameter of the large aspect ratio pipe and the outer diameter of the arc target is controlled within 80-100 mm.

[0021] Furthermore, the cooling system includes cooling water pipes and a circulating water pump; part of the cooling water pipes are arranged in a ring on the sealing plates at both ends of the vacuum chamber, part of the cooling water pipes are arranged in the arc target of the arc ion plating target system to control the target temperature, and part of the cooling water pipes are arranged in the balancer and the shock absorber; the cooling water in the cooling water pipes is circulated by the circulating water pump.

[0022] Furthermore, the thermocouple is installed in the thermocouple installation hole of the sealing plate at the front end of the vacuum chamber. The extension length of the thermocouple is adjustable. When measuring temperature, it needs to penetrate into 1 / 2 of the length of the large aspect ratio pipe.

[0023] An arc ion plating method for the inner cavity of a pipe with a complex structure having a large aspect ratio, comprising:

[0024] For the pipe fittings with a large aspect ratio to be processed, firstly, sealing plates matching the dimensions of the two ends of the pipe fittings with a large aspect ratio are prefabricated, and the sealing plates are fixed to the two ends of the pipe fittings with a large aspect ratio to form a vacuum chamber, and the vacuum chamber is installed on a fixing frame through a bearing device, and the vacuum chamber is fixed on a slide rail installed with a rotating motor and a motor balancing and shock absorbing system through the fixing frame; then, the vacuum chamber is connected to a vacuum pumping system, an arc ion plating target system, an air supply system, a temperature measurement system and a motor balancing and shock absorbing system, and the cooling water pipe in the cooling system is connected to a circulating water pump;

[0025] Open the circulating water pump, mechanical pump and pre-pumping valve to evacuate the vacuum chamber to 4-5 Pa, then close the pre-pumping valve, open the molecular pump and the front stage valve, evacuate to 1-2 Pa, then open the high stage valve to evacuate the vacuum chamber to 1×10 -3 Pa; open the gas cylinder valve and the flow meter, adjust the gas flow input from the gas cylinder to the vacuum chamber, observe the gas flow and the vacuum degree in the vacuum chamber through the flow meter and two sets of vacuum gauges, and then turn on the arc ion plating target system; then turn on the rotating motor, the balancer and the motor balance damping system, adjust the arc target sputtering cleaning voltage, and then set the rotating speed of the rotating motor, first use the plasma sputtered by the arc target to bombard the inner surface of the large aspect ratio pipe to remove surface pollutants and clean the inner surface of the pipe, adjust the voltage of the arc target to an appropriate value according to the elemental composition of the coating to be deposited, and then reduce the rotating speed of the rotating motor to prepare the coating on the inner wall of the large aspect ratio pipe according to the specified thickness.

[0026] Furthermore, the cleaning time is 1-2 cycles of the arc target from the front end to the rear end of the vacuum chamber.

[0027] The present invention has the following technical features:

[0028] Compared with the existing technology, this solution has a wider range of applications, higher economic efficiency, simple device operation, high mobility, and smaller footprint, making it easier to promote. It has lower requirements for target materials and can adapt to the preparation of inner cavity coatings for pipes of different lengths. The arc ion plating technology used in this solution has a faster coating speed and a higher bonding strength between the coating and the substrate. At the same time, the arc ion plating coating preparation technology is economical and environmentally friendly. In addition, large aspect ratio pipes are directly placed on the carrier device, without vibration, and are easy to operate, which helps to achieve unmanned automated processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the device of the present invention.

[0030] Explanation of the numbers in the figure: 1 molecular pump, 2 mechanical pump, 3 temperature controller, 4 thermocouple, 5 arc target, 6 vacuum chamber, 7 connecting rod, 8 bearing device, 9 fixing frame, 10 gas supply pipe, 11 gas flow meter, 12 gas cylinder, 13 rotating motor, 14 balancer and shock absorber, 15 bracket with rollers, 16 slide rail, 17 exhaust pipe, 18 pre-extraction valve, 19 high valve, 20 front valve. DETAILED DESCRIPTION

[0031] In view of the problems existing in the prior art, the present invention provides an arc ion plating device and method for the surface of a complex inner cavity of a pipe with a large aspect ratio, which can prepare a uniform and dense protective coating such as Cr on the complex inner cavity of a pipe with a large aspect ratio; the device and method have the characteristics of good flexibility, easy operation, fast plating speed, uniform and dense coating and high bonding strength with the substrate; the use of the device and the specific process is not only environmentally friendly, but also can avoid hydrogen permeation of the substrate, and its wear and corrosion resistance is significantly better than that of traditional electroplated Cr coating and magnetron sputtering α-Ta coating.

[0032] See attached Figure 1 The present invention provides an arc ion plating device for a large aspect ratio pipe with a complex structure, comprising a sealing system, a vacuum system, an arc ion plating target system, a cooling system, a gas supply system, a temperature measurement system and a motor balancing and damping system, wherein:

[0033] The sealing system includes a sealing plate for sealing both ends of the large aspect ratio pipe to be processed. The sealed large aspect ratio pipe serves as a vacuum chamber 6 and is mounted on a fixed frame 9 through a bearing device 8; wherein the sealing plate at the front end of the large aspect ratio pipe has a vacuum connection hole reserved in the middle, a thermocouple 4 mounting hole and a pair of vacuum gauge mounting holes reserved in the lower part; the sealing plate at the rear end has an ion plating connection hole reserved in the middle, an air supply hole and a pair of vacuum gauge mounting holes reserved in the lower part. The function of the sealing system is to seal the vacuum system, the arc ion plating target system and the vacuum chamber 6, and provide basic conditions for establishing a vacuum degree. In this embodiment, the bearing device 8 adopts an arc-shaped fixing card, which is supported at the bottom of the side wall of the vacuum chamber 6, so that the axial direction of the vacuum chamber 6 is parallel to the horizontal plane.

[0034] The vacuum pumping system includes a mechanical pump 2, a molecular pump 1 and two sets of vacuum gauges; an air pumping pipe 17 is connected to the vacuum pumping connection hole, the air pumping port of the mechanical pump 2 is connected to the air pumping pipe 17 through a pipeline equipped with a pre-pumping valve 18, and the air outlet of the mechanical pump 2 is connected to the atmosphere; the air pumping port of the molecular pump 1 is connected to the air pumping pipe 17 through a pipeline equipped with a high valve 19, and the air outlet of the molecular pump 1 is connected to the air pumping port of the mechanical pump 2 through a pipeline equipped with a pre-stage valve 20; the mechanical pump 2 is used to pump the air pressure of the vacuum chamber 6 from atmospheric pressure to 4-5Pa, and the molecular pump 1 is used to pump the air pressure of the vacuum chamber 6 from 4-5Pa to 1×10 -3Pa; two groups of vacuum silicon tubes are respectively installed in the vacuum gauge installation holes at the front end and the rear end of the vacuum chamber 6, and are arranged along the length direction of the vacuum chamber 6; each group of vacuum silicon tubes includes a low vacuum gauge and a high vacuum gauge; the two groups of vacuum gauges are used to measure the vacuum degree of the vacuum chamber 6. When the vacuum degrees of the two groups of vacuum gauges at the front and rear ends of the vacuum chamber 6 are consistent or close, the coating preparation process is helpful to improve the overall performance of the coating. The purpose of such assembly is to ensure the uniformity of molecules, ions, etc. inside the vacuum chamber 6.

[0035] The arc ion plating target system includes a cylindrical arc target 5 and a permanent magnetic field built into the arc target 5, wherein the arc target 5 is arranged inside the vacuum chamber 6 and installed at the front end of a connecting rod 7; the connecting rod 7 passes through the ion plating connecting hole on the sealing plate at the rear end of the vacuum chamber 6, and the connecting rod 7 and the ion plating connecting hole are threaded and sealed, and the rear end of the connecting rod 7 is located outside the vacuum chamber 6 and installed on the output shaft of the rotating motor 13, so as to realize that the arc target 5 rotates around the axis of the large aspect ratio pipe and moves at a uniform speed in the direction of the axis of the large aspect ratio pipe at the same time; the magnetic field direction of the permanent magnetic field is perpendicular to the axis of the arc target 5. The cylindrical arc target 5 can realize the uniform deposition of the complex inner cavity coating of the large aspect ratio pipe, and the arrangement direction of the permanent magnetic field can realize the uniform motion ablation and uniform sputtering of the arc spot on the surface of the arc target 5. The axis of the arc target 5 coincides with the axis of the vacuum chamber 6, and the difference between the inner diameter of the large aspect ratio pipe and the outer diameter of the arc target 5 should be controlled within 80-100mm.

[0036] The motor balancing and damping system includes a balancer and a damper 14, on which the rotating motor 13 is mounted, and the bottom of the rotating motor 13, the balancer and the damper 14 is mounted on a slide rail 16 through a bracket 15 with rollers, and the slide rail 16 is arranged parallel to the axial direction of the vacuum chamber 6, so that the rotating motor 13, the balancer and the damper 14 can move axially as a whole under the threaded cooperation between the connecting rod 7 and the ion plating connecting hole. The motor balancing and damping system is used to ensure the stability of the rotation and movement of the arc target 5 during the arc ion plating coating preparation process.

[0037] The cooling system is used to cool the sealing system, the arc ion plating target system and the motor balancing and shock absorbing system; the cooling system includes cooling water pipes and a circulating water pump; some cooling water pipes are arranged in a ring on the sealing plates at both ends of the vacuum chamber 6 to ensure sufficient cooling of the sealing plates and to ensure the long life and reliability of the high-temperature vacuum sealing rubber rings at each interface; some cooling water pipes are arranged in the arc target 5 of the arc ion plating target system to timely control the target temperature, which helps to fully ionize the target, reduce coating defects and improve coating performance; some cooling water pipes are arranged in the balancer and shock absorber 14; the cooling water in the cooling water pipe is circulated by the circulating water pump to achieve cooling of different components.

[0038] The gas supply system includes a gas cylinder 12, a gas flow meter 11 and a gas supply pipe 10. The gas cylinder 12 is connected to the gas supply hole on the rear end sealing plate of the vacuum chamber 6 through the gas supply pipe 10. The gas flow meter 11 is installed on the gas supply pipe 10, and a gas cylinder valve is installed on the gas cylinder 12. The gas cylinder 12 is an argon gas cylinder 12, a nitrogen gas cylinder 12, etc., which is used to quantitatively and constantly input the gas required for preparing the coating into the vacuum chamber 6.

[0039] The temperature measurement system includes a thermocouple 4 and a temperature controller 3, which are used to measure the real-time temperature of the vacuum chamber 6; the thermocouple 4 is connected to the temperature controller 3, and the thermocouple 4 is installed in the thermocouple 4 mounting hole of the sealing plate at the front end of the vacuum chamber 6. The extension length of the thermocouple 4 is adjustable. When measuring the temperature, it is necessary to penetrate into 1 / 2 of the length of the large aspect ratio pipe fitting, which is used to adapt to the temperature test in the vacuum chamber 6 of pipe fittings of different lengths.

[0040] The invention has a wider application range, lower requirements on target materials, and can be adapted to the preparation of inner cavity coatings of pipes of different lengths. Arc ion plating technology has fast coating speed and good economy, and the bonding strength between the coating and the substrate is higher; in addition, large aspect ratio pipes are directly placed on the carrier 8, without vibration, simple operation, and help to achieve unmanned automated processing. During the whole preparation process, the large aspect ratio pipe to be plated is used as a vacuum chamber 6 and placed on a carrying device 8. One end of the vacuum chamber 6 is connected to the vacuum pumping system and connected by an adapter to ensure sealing; the other end of the vacuum chamber 6 is connected to the arc ion plating target system and connected by an adapter to ensure sealing; the arc target 5 is placed inside the pipe vacuum chamber 6, and the arc target 5 is built with a permanent magnetic field and a cooling water pipe perpendicular to the axis of the arc target 5 to ensure uniform sputtering of the arc target 5 and improve the utilization rate of the target; the built-in cooling water pipe is connected to the external circulating water pump through a connecting rod 7 and circulates and cools; the connecting rod 7 is connected to the ion plating connection hole through a threaded seal to realize the arc target 5 rotating around the pipe axis and moving at a uniform speed along the pipe axis at the same time. This design makes it unnecessary for the arc ion plating target to be consistent with the pipe length, which improves the versatility of the target. After the temperature measurement system and the motor balance and shock absorption system are installed, the arc ion plating coating can be prepared.

[0041] On the basis of the above technical solution, the present invention further provides an arc ion plating method for the inner cavity of a complex structure of a large aspect ratio pipe, comprising:

[0042] For the pipe fittings with a large aspect ratio to be processed, firstly, sealing plates matching the dimensions of the two ends of the pipe fittings with a large aspect ratio are prefabricated, and the sealing plates are fixed to the two ends of the pipe fittings with a large aspect ratio to form a vacuum chamber 6, and the vacuum chamber 6 is installed on a fixing frame 9 through a bearing device 8, and the vacuum chamber 6 is fixed on a slide rail 16 equipped with a rotating motor 13 and a motor balancing and shock absorbing system through the fixing frame 9; then, the vacuum chamber 6 is connected to a vacuum pumping system, an arc ion plating target system, an air supply system, a temperature measurement system and a motor balancing and shock absorbing system, and the cooling water pipe in the cooling system is connected to a circulating water pump;

[0043] Open the circulating water pump, mechanical pump 2 and pre-pumping valve 18, evacuate the vacuum chamber 6 to 4-5 Pa, then close the pre-pumping valve 18, open the molecular pump 1 and the front valve 20, evacuate to 1-2 Pa, then open the high valve 19, evacuate the vacuum chamber 6 to 1×10 -3 Pa; open the gas cylinder valve, adjust the gas flow rate input from the gas cylinder 12 into the vacuum chamber 6, observe the gas flow rate and the vacuum degree in the vacuum chamber 6 through the gas flow meter 11 and two sets of vacuum gauges to be stable (the reading of the gas flow meter 11 is stable, and the readings of the two sets of vacuum gauges are consistent), and then turn on the arc ion plating target system; then turn on the rotating motor 13, the balancer and the motor balance and shock absorption system, adjust the sputtering cleaning voltage of the arc target 5, and then set the speed of the rotating motor 13, first use the plasma sputtered by the arc target 5 to bombard the inner surface of the large aspect ratio pipe to remove surface contaminants and clean the inner surface of the pipe, and the cleaning time is 1-2 cycles of the arc target 5 from the front end to the rear end of the vacuum chamber 6; adjust the voltage of the arc target 5 to an appropriate value according to the elemental composition of the coating to be deposited, and then reduce the speed of the rotating motor 13, and prepare the coating on the inner wall of the large aspect ratio pipe according to the specified thickness.

[0044] The present invention can realize the preparation of arc ion plating coatings on the complex inner cavity surfaces of pipes with large aspect ratios. At the same time, the device has high mobility, excellent comprehensive performance of the prepared coatings, and can also avoid the hydrogen permeation problem on the pipe surface and environmental pollution problems caused by Cr electroplating technology.

[0045] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An arc ion plating device for a complex structure inner cavity of a pipe with a large aspect ratio, characterized in that: It includes sealing system, vacuum system, arc ion plating target system, cooling system, gas supply system, temperature measurement system and motor balance and vibration reduction system, among which: The sealing system comprises sealing plates for sealing both ends of the large aspect ratio pipe to be processed, and the sealed large aspect ratio pipe serves as a vacuum chamber (6) and is mounted on a fixing frame (9) via a carrying device (8); The vacuum pumping system comprises a mechanical pump (2), a molecular pump (1) and two sets of vacuum gauges; the mechanical pump (2) and the molecular pump (1) are connected to the front end of the vacuum chamber (6) and are used to perform vacuum pumping in the vacuum chamber (6); the two sets of vacuum gauges are respectively installed at the front end and the rear end of the vacuum chamber (6) along the length direction of the vacuum chamber (6) and are used to measure the vacuum degree of the vacuum chamber (6); The arc ion plating target system comprises a cylindrical arc target (5) and a permanent magnetic field built into the arc target (5), wherein the arc target (5) is arranged inside a vacuum chamber (6) and mounted on the front end of a connecting rod (7); the connecting rod (7) passes through the rear end of the vacuum chamber (6), and the rear end of the connecting rod (7) is located outside the vacuum chamber (6) and mounted on the output shaft of a rotating motor (13), so that the arc target (5) can rotate around the axis of a large aspect ratio pipe and move at a uniform speed along the axis of the large aspect ratio pipe at the same time; the magnetic field direction of the permanent magnetic field is perpendicular to the axis of the arc target (5); The motor balancing and shock absorbing system comprises a balancer and a shock absorber (14), wherein the rotating motor (13) is mounted on the balancer and the shock absorber (14), and the bottoms of the rotating motor (13), the balancer and the shock absorber (14) are mounted on a slide rail (16) via a bracket (15) with rollers, and the slide rail (16) is arranged parallel to the axial direction of the vacuum chamber (6); The cooling system is used to cool the sealing system, arc ion plating target system and motor balance and vibration reduction system; The gas supply system comprises a gas cylinder (12), a gas flow meter (11) and a gas supply pipe (10); the gas cylinder (12) is connected to the rear end of the vacuum chamber (6) via the gas supply pipe (10), the gas flow meter (11) is installed on the gas supply pipe (10), and a gas cylinder valve is installed on the gas cylinder (12); The temperature measurement system comprises a thermocouple (4) and a temperature controller (3), and is used to measure the real-time temperature of the vacuum chamber (6).

2. The arc ion plating device for complex structure inner cavity of pipes with large aspect ratio according to claim 1 is characterized in that: The sealing plate at the front end of the large aspect ratio pipe has a vacuum connection hole in the middle, a thermocouple (4) installation hole and a pair of vacuum gauge installation holes in the lower part; the sealing plate at the rear end has an ion plating connection hole in the middle, an air supply hole and a pair of vacuum gauge installation holes in the lower part.

3. The arc ion plating device for complex structure of large aspect ratio pipe according to claim 1, characterized in that: The bearing device (8) adopts an arc-shaped fixing card and is supported on the bottom of the side wall of the vacuum chamber (6), so that the axial direction of the vacuum chamber (6) is parallel to the horizontal plane.

4. The arc ion plating device for complex structure inner cavity of pipe with large aspect ratio according to claim 1 is characterized in that: The vacuum connection hole is connected to an exhaust pipe (17); the exhaust port of the mechanical pump (2) is connected to the exhaust pipe (17) via a pipeline equipped with a pre-exhaust valve (18); the air outlet of the mechanical pump (2) is connected to the atmosphere; the exhaust port of the molecular pump (1) is connected to the exhaust pipe (17) via a pipeline equipped with a high-pressure valve (19); the air outlet of the molecular pump (1) is connected to the exhaust port of the mechanical pump (2) via a pipeline equipped with a pre-stage valve (20).

5. The arc ion plating device for complex structure inner cavity of large aspect ratio pipe according to claim 1, characterized in that: The mechanical pump (2) is used to pump the air pressure of the vacuum chamber (6) from atmospheric pressure to (4) to (5) Pa, while the molecular pump (1) is used to pump the air pressure of the vacuum chamber (6) from 4 to 5 Pa to 1×10 -3 Pa.

6. The arc ion plating device for complex structure inner cavity of pipe with large aspect ratio according to claim 1, characterized in that: The connecting rod (7) passes through the ion-plating connecting hole on the sealing plate at the rear end of the vacuum chamber (6), and the connecting rod (7) and the ion-plating connecting hole are threadedly sealed.

7. The arc ion plating device for complex structure inner cavity of pipe with large aspect ratio according to claim 1, characterized in that: The axis of the arc target (5) coincides with the axis of the vacuum chamber (6), and the difference between the inner diameter of the large aspect ratio pipe and the outer diameter of the arc target (5) is controlled within 80-100 mm.

8. The arc ion plating device for the inner cavity of a pipe with a complex structure having a large aspect ratio according to claim 1, characterized in that: The cooling system comprises cooling water pipes and a circulating water pump; part of the cooling water pipes are arranged in a ring on sealing plates at both ends of a vacuum chamber (6), part of the cooling water pipes are arranged in an arc target (5) of an arc ion plating target system to control the temperature of the target, and part of the cooling water pipes are arranged in a balancer and a shock absorber (14); the cooling water in the cooling water pipes is circulated by the circulating water pump.

9. The arc ion plating device for complex structure inner cavity of pipe with large aspect ratio according to claim 1, characterized in that: The thermocouple (4) is installed in the thermocouple (4) installation hole of the front end sealing plate of the vacuum chamber (6). The extension length of the thermocouple (4) is adjustable and needs to penetrate into 1 / 2 of the length of the large aspect ratio pipe when measuring temperature.

10. A method for arc ion plating in the inner cavity of a complex structure of a pipe with a large aspect ratio, characterized in that: include: For a pipe fitting with a large aspect ratio to be processed, firstly, sealing plates matching the dimensions of the two ends of the pipe fitting with a large aspect ratio are prefabricated, and the sealing plates are fixed to the two ends of the pipe fitting with a large aspect ratio to form a vacuum chamber (6), the vacuum chamber (6) is installed on a fixing frame (9) via a bearing device (8), and the vacuum chamber (6) is fixed on a slide rail (16) on which a rotating motor (13) and a motor balancing and damping system are installed via the fixing frame (9); then, the vacuum chamber (6) is connected to a vacuum pumping system, an arc ion plating target system, an air supply system, a temperature measurement system and a motor balancing and damping system, and a cooling water pipe in a cooling system is connected to a circulating water pump; The circulating water pump, mechanical pump (2) and pre-pumping valve (18) are turned on to evacuate the vacuum chamber (6) to 4-5 Pa, and then the pre-pumping valve (18) is closed. The molecular pump (1) and the fore valve (20) are turned on to evacuate the vacuum chamber to 1-2 Pa, and then the high valve (19) is turned on to evacuate the vacuum chamber 6 to 1×10 -3 Pa; open the gas cylinder valve and the flow meter, adjust the gas flow rate input from the gas cylinder (12) into the vacuum chamber (6), observe the gas flow rate and the vacuum degree in the vacuum chamber (6) through the flow meter and two sets of vacuum gauges to be stable, and then turn on the arc ion plating target system; then turn on the rotating motor (13), the balancer and the motor balance damping system, adjust the sputtering cleaning voltage of the arc target (5), and then set the rotation speed of the rotating motor (13), first use the plasma sputtered by the arc target (5) to bombard the inner surface of the large aspect ratio pipe to remove surface contaminants and clean the inner surface of the pipe, adjust the voltage of the arc target (5) to a suitable value according to the elemental composition of the coating to be deposited, and then reduce the rotation speed of the rotating motor (13) to prepare the coating on the inner wall of the large aspect ratio pipe according to the specified thickness.

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